Syringes are widely used for the administration of drugs or other substances to, or for the withdrawal of fluids from, a body. Syringes are also used for a variety of health industry and other purposes as well. Typically, a syringe includes a barrel and a plunger. The plunger is reciprocally disposed within the barrel, with the plunger protruding from the proximal end of the barrel throughout its range of movement. To utilize the syringe a needle will generally be attached to the distal end of the syringe barrel, the needle being coaxial with the central axis of the barrel. The syringe may be provided with the needle pre-placed in this location, with a protective cap or sheath covering the needle. Alternatively, and more commonly, a needle with an associated sheath is attached to the distal end of a syringe barrel prior to use.
Generally, the syringe barrel and needle sheath are mass produced from a low cost material, such as polypropylene, by a cost-efficient method such as injection molding. The needle is made of a suitable material, such as 304 stainless steel.
When administering a medicine the empty syringe is often filled from a vial containing the medicine. Medicine vials usually have a membrane covering the liquid opening. The needle is used to pierce the membrane to draw the medicine into the syringe.
A problem with drawing medicine from a vial is that the needle can be dulled when piercing the membrane. The dull needle can cause obvious problems when used for injecting the medicine into a patient.
One known solution to the problem is to remove the dulled needle and replace it with a fresh needle. This practice is, however, time consuming and also requires a supply of fresh needles. Furthermore, the dull needles are discarded individually presenting another possible hazard.
Subsequent to use the syringe needle will often be recapped and discarded in a suitable disposal container. In some settings the needle may be clipped prior to recapping, in an effort to preclude any illicit use of the needle after its disposal; however, clipping can release toxic and/or infectious aerosolization mists.
For many applications a syringe with a coaxial needle will suffice. However, there are numerous situations in which this embodiment presents significant obstacles to the effective use of the syringe. The typical syringe with a coaxial needle may have limited use when administering fluids intravenously, or particularly subcutaneously. The foregoing problems are exacerbated when larger volumes of fluid, and consequently larger diameter syringe barrels, are utilized.
Furthermore, very serious, even life threatening, problems may be associated with the attachment, but more particularly with the removal, of a needle from such a syringe. The problems associated with the recapping and disposal of previously-used syringe needles are also severe. In the medical industry an exceptionally high percentage of job-related needle sticks occur during the process of needle recapping. Such needle sticks may serve as a mode for the spread of infectious disease, and are accordingly of great concern. The clipping procedure may also lead to needle sticks and/or toxic or infectious aerosolization exposure; if the syringe barrel is not also clipped it may be illicitly used once a functional needle is obtained.